Electroconductive sheet and touch panel

ABSTRACT

The present invention provides an electroconductive sheet and a touch panel which do not impair visibility in a vicinity of an electrode terminal in a sensing region. In an electroconductive sheet which has an electrode pattern constructed of a metal thin wire and an electrode terminal that is electrically connected to an end of the electrode pattern, a transmittance of the electrode pattern is 83% or more, and when the transmittance of the electrode pattern is represented by a %, a transmittance of the electrode terminal is controlled to be (a-20)% or more and (a-3)% or less.

This application is a divisional of U.S. application Ser. No.14/264,879, filed Apr. 29, 2014, which is a continuation ofPCT/JP2012/082030, filed Dec. 11, 2012, which claims priority from JP2011-276069 and JP 2011-276070, both filed Dec. 16, 2011, and JP2011-281926, filed Dec. 22, 2011, all of which are incorporated hereinby reference in their entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an electroconductive sheet and a touchpanel, and relates to, for instance, an electroconductive sheet which isused in a projected capacitive touch panel and the touch panel.

2. Description of the Related Art

A transparent electroconductive film which uses a metal thin wire hasbeen continuously studied as described in U.S. Patent ApplicationPublication No. 2004/0229028 and International Publication No. WO2006/001461, for instance.

Recently, a touch panel has received attention. The touch panel ismainly applied to devices having a small size such as a PDA (personaldigital assistant) and a cellular phone, but is considered to beprogressively applied to devices having a larger size such as a displayfor a personal computer.

In such a trend of the future, a conventional electrode employs ITO(indium tin oxide). The ITO has problems in that the resistance islarge, a transmission speed of an electric current between electrodesbecomes slow, and a response speed (period of time between the time whenfinger has touched and the time when position is detected) becomes slow,as the application size increases.

Then, it is considered to lower the surface resistance by an electrodeconstructed of the metal thin wire. As for a touch panel in which themetal thin wire is used for the electrode, Japanese Patent ApplicationLaid-Open No. H5-224818, U.S. Pat. No. 5,113,041, InternationalPublication No. WO 1995/27334, U.S. Patent Application Publication No.2004/0239650, U.S. Pat. No. 7,202,859, International Publication No. WO1997/18508 and Japanese Patent Application Laid-Open No. 2003-099185 areknown, for instance.

SUMMARY OF THE INVENTION

By the way, a sensing electrode of a touch panel has an electrodepattern which includes, at least, a metal thin wire at least in a touchregion and an electrode terminal which is electrically connected to anend of the electrode pattern. The electrode terminal is a thick terminal(solid terminal) so as to have high electroconductivity. Therefore, whena display and the touch panel are operated in combination, the electrodeterminal shields light emitted from the display in a sensing region(electrode pattern). Accordingly, a darkened portion appears in avicinity of the electrode terminal in the sensing region, and thedisplay occasionally becomes less-viewable.

The present invention has been made in consideration of such problems,and aims to provide an electroconductive sheet and a touch panel whichdo not impair visibility in the vicinity of the electrode terminal inthe sensing region.

A first electroconductive sheet according to the present invention is anelectroconductive sheet which includes: an electrode pattern constructedof a metal thin wire; and an electrode terminal that is electricallyconnected to an end of the electrode pattern, wherein a transmittance ofthe electrode pattern is 83% or more, and when the transmittance of theelectrode pattern is represented by a %, a transmittance of theelectrode terminal is (a-20)% or more and (a-3)% or less.

The first electroconductive sheet of another aspect according to thepresent invention is an electroconductive sheet which includes: anelectrode pattern constructed of a metal thin wire; and an electrodeterminal that is electrically connected to an end of the electrodepattern, wherein an aperture ratio of the electrode pattern is 90% ormore, and when the aperture ratio of the electrode pattern isrepresented by b %, an aperture ratio of the electrode terminal is(b-20)% or more and (b-0.1)% or less.

In the above described first electroconductive sheet according to thepresent invention, it is preferable that the electrode terminal includea mesh shape formed of lattices constructed of a metal thin wire, themetal thin wire has a line width of 30 μm or less, and the metal thinwire is made from an opaque material.

A first touch panel according to the present invention is a touch panelhaving an electroconductive sheet which includes: an electrode patternthat is provided in a sensing region and is constructed of a metal thinwire; and an electrode terminal that is provided in an outside of thesensing region and is electrically connected to an end of the electrodepattern, wherein a transmittance of the electrode pattern is 83% ormore, and when the transmittance of the electrode pattern is representedby a %, a transmittance of the electrode terminal is (a-20)% or more and(a-3)% or less.

A first touch panel of another aspect according to the present inventionis a touch panel having an electroconductive sheet which includes: anelectrode pattern that is provided in a sensing region and isconstructed of a metal thin wire; and an electrode terminal that isprovided in an outside of the sensing region and is electricallyconnected to an end of the electrode pattern, wherein an aperture ratioof the electrode pattern is 90% or more, and when the aperture ratio ofthe electrode pattern is represented by b %, an aperture ratio of theelectrode terminal is (b-20)% or more and (b-0.1)% or less.

A second electroconductive sheet according to the present invention isan electroconductive sheet including: an electrode pattern constructedof a metal thin wire; and an electrode terminal that is electricallyconnected to an end of the electrode pattern, wherein the electrodeterminal includes a frame shape constructed of a metal thin wire.

In the second electroconductive sheet according to the presentinvention, preferably, when a line width of the thin wire of theelectrode pattern is represented by a (μm), a line width b (μm) of theframe shape of the electrode terminal satisfies b≧2a or b≧a+5 (μm). Theline width a (μm) of the thin wire of the electrode pattern ispreferably 30 μm or less.

The second electroconductive sheet according to the present invention,preferably further including a mesh shape provided in the frame shape ofthe electrode terminal constructed of the metal thin wire, the meshshape which is formed of lattices constructed of a metal thin wire.

A second touch panel according to the present invention is a touch panelhaving an electroconductive sheet which includes: an electrode patternthat is provided in a sensing region and is constructed of a metal thinwire; and an electrode terminal that is provided in an outside of thesensing region and is electrically connected to an end of the electrodepattern, wherein the electrode terminal includes a frame shapeconstructed of a metal thin wire.

A third electroconductive sheet according to the present invention is anelectroconductive sheet including: an electrode pattern constructed of ametal thin wire; and an electrode terminal that is electricallyconnected to an end of the electrode pattern, wherein the electrodeterminal includes a mesh shape formed of lattices constructed of a metalthin wire.

In the third electroconductive sheet according to the present invention,it is preferable that the electrode pattern be the mesh shape formed oflattices, and a pitch of the mesh shape formed of the lattices of theelectrode terminal be denser than a pitch of the mesh shape formed ofthe lattices of the electrode pattern. The pitch of the mesh shapeformed of the lattices of the electrode terminal is preferably notlarger than ¾ of the pitch of the mesh shape formed of the lattices ofthe electrode pattern, more preferably is not larger than ⅔ thereof, andfurther more preferably is not larger than ½ thereof. The specific pitchof the mesh shape of the electrode terminal is 50 μm or more and 300 μmor less, and more preferably is 50 μm or more and 250 μm or less.

The third electroconductive sheet according to the present invention,preferably further including a frame shape constructed of a metal thinwire, the frame shape which is provided as an outer frame of the meshshape formed of the lattices of the electrode terminal.

In the third electroconductive sheet according to the present invention,it is preferable that a surface resistance value of the electrodeterminal be 4 Ω/sq. or more and 80 Ω/sq. or less.

A third touch panel according to the present invention is a touch panelhaving an electroconductive sheet which includes: an electrode patternthat is provided in a sensing region and is constructed of a metal thinwire; and an electrode terminal that is provided in an outside of thesensing region and is electrically connected to an end of the electrodepattern, wherein the electrode terminal includes a mesh shape formed oflattices constructed of a metal thin wire.

The electroconductive sheet and the touch panel according to the presentinvention can prevent visibility from being impaired in the vicinity ofan electrode terminal in a sensing region.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view illustrating one example of an electrode terminalof an electroconductive sheet for a touch panel.

FIG. 2 is a plan view illustrating another example of the electrodeterminal of the electroconductive sheet for a touch panel.

FIG. 3 is a plan view illustrating another example of the electrodeterminal of the electroconductive sheet for a touch panel.

FIG. 4A is an exploded perspective view illustrating theelectroconductive sheet for a touch panel, while omitting a part thereof(Part 1).

FIG. 4B is an exploded perspective view illustrating theelectroconductive sheet for a touch panel, while omitting a part thereof(Part 2).

FIG. 5A is a sectional view illustrating one example of theelectroconductive sheet for a touch panel, while omitting a partthereof.

FIG. 5B is a sectional view illustrating another example of theelectroconductive sheet for a touch panel, while omitting a partthereof.

FIG. 6A is a plan view illustrating an example of a first electrodepattern formed on a first electroconductive sheet.

FIG. 6B is a plan view illustrating an example of a second electrodepattern formed on a second electroconductive sheet.

FIG. 7 is a plan view illustrating an example of the electroconductivesheet for a touch panel, which is formed of the first electroconductivesheet and the second electroconductive sheet in combination, whileomitting a part thereof.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Preferable embodiments according to the present invention are describedbelow with reference to the attached drawings. The present invention isdescribed below with reference to preferable embodiments, but can bemodified by many techniques without exceeding the scope of the presentinvention, and can make use of other embodiments than the presentembodiment. Accordingly, all modifications in the scope of the presentinvention are included in the claims.

The electroconductive sheet and the touch panel according to the presentembodiment are described below with reference to FIG. 1 to FIG. 7.Incidentally, “to” which indicates a range between numeric values in thepresent specification is used as meaning including the numeric valuesdescribed in front and back of “to”, as the lower limit and the upperlimit.

As is illustrated in FIG. 1 to FIG. 3, a first electroconductive sheet10 for a touch panel according to the present embodiment is anelectroconductive sheet 12A (12B) which has, on a substrate 14A, anelectrode pattern 16A (16B) constructed of a metal thin wire and anelectrode terminal 60A (60B) that is electrically connected to an end ofthe electrode pattern 16A (16B), wherein a transmittance of theelectrode pattern 16A (16B) is 83% or more, and when the transmittanceof the electrode pattern 16A (16B) is represented by a %, atransmittance of the electrode terminal 60A (60B) is (a-20)% or more and(a-3)% or less. In addition, as another aspect, the firstelectroconductive sheet 10 for a touch panel according to the presentembodiment is an electroconductive sheet 12A (12B) which has, on asubstrate 14A, an electrode pattern 16A (16B) constructed of a metalthin wire and an electrode terminal 60A (60B) that is electricallyconnected to an end of the electrode pattern 16A (16B), wherein anaperture ratio of the electrode pattern 16A (16B) is 90% or more, andwhen the aperture ratio of the electrode pattern 16A (16B) isrepresented by b %, an aperture ratio of the electrode terminal 60A(60B) is (b-20)% or more and (b-0.1)% or less.

As is illustrated in FIG. 1 and FIG. 2, a second electroconductive sheet10 for a touch panel according to the present embodiment is anelectroconductive sheet 12A (12B) which has an electrode pattern 16A(16B) constructed of a metal thin wire and an electrode terminal 60A(60B) that is electrically connected to an end of the electrode pattern16A (16B), wherein the electrode terminal 60A (60B) includes a frameshape 64 constructed of a metal thin wire.

As is illustrated in FIG. 1 and FIG. 2, a third electroconductive sheet10 for a touch panel according to the present embodiment is anelectroconductive sheet 12A (12B) which has an electrode pattern 16A(16B) constructed of a metal thin wire and an electrode terminal 60A(60B) that is electrically connected to an end of the electrode pattern16A (16B), wherein the electrode terminal 60A (60B) includes a meshshape 66 formed of lattices 68 constructed of a metal thin wire.

In addition, the electroconductive sheet 10 for a touch panel accordingto the present embodiment is configured by stacking (laminating) a firstelectroconductive sheet 12A and a second electroconductive sheet 12B, asis illustrated FIG. 4A or FIG. 4B and FIG. 5A.

The first electroconductive sheet 12A has a first electrode pattern 16Aformed on one principal surface of a first transparent substrate 14A(see FIG. 5A), as is illustrated in FIG. 4A, FIG. 4B and FIG. 6A. Thefirst electrode pattern 16A is constructed of a large number of latticesformed of a metal thin wire. The first electrode pattern 16A has two ormore first electroconductive patterns 18A which extend each in a firstdirection (x-direction) and are arrayed in a second direction(y-direction) perpendicular to the first direction, and firstnon-electroconductive patterns 20A which electrically separate each ofthe first electroconductive patterns 18A. In the firstnon-electroconductive pattern 20A, a plurality of break portions 22A areformed in places other than intersections of the metal thin wires. Eachof the first electroconductive patterns 18A is electrically separated bythe plurality of break portions 22A.

The metal thin wire which constitutes the first electrode pattern 16Ahas a line width of 30 μm or less, preferably of 15 μm or less, furtherpreferably of 10 μm or less, further preferably of 9 μm or less, andfurther preferably of 7 μm or less. A lower limit of the line width ispreferably 1 μm. Incidentally, the first electroconductive pattern 18Aand the first non-electroconductive pattern 20A have substantially thesame line width, but in FIG. 6A, in order to clarify the firstelectroconductive pattern 18A and the first non-electroconductivepattern 20A, the patterns are exaggeratedly illustrated so that the linewidth of the first electroconductive pattern 18A is thick and the linewidth of the first non-electroconductive pattern 20A is thin. The linewidth of the first electroconductive pattern 18A and the line width ofthe first non-electroconductive pattern 20A may be the same or may bedifferent. The line widths of both the patterns are preferably the same.The reason is because when the line widths are different, visibility isoccasionally aggravated. The metal thin wire of the first electrodepattern 16A is made from an electroconductive material of a metalmaterial such as gold, silver and copper, and a metal oxide, and is madefrom an opaque electroconductive material.

The first electrode pattern 16A includes a plurality of lattices 24Awhich are constructed of intersecting metal thin wires. The lattice 24Aincludes an opening region which is surrounded by the metal thin wire.The lattices 24A have a lattice pitch Pa of 300 μm or more and 800 μm orless, and preferably of 400 μm or more and 600 μm or less. The lattices24A of the first electroconductive pattern 18A and the lattices 24A ofthe first non-electroconductive pattern 20A have substantially the samesize.

The lattice 24A of the first non-electroconductive pattern 20A has breakportions 22A in places other than intersections of the metal thin wires.All of the lattices 24A which constitute the first non-electroconductivepattern 20A do not need to have the break portion 22A as long as thefirst non-electroconductive pattern 20A may achieve electrical isolationbetween the adjacent first electroconductive patterns 18A. The length ofthe break portion 22A is preferably 60 μm or less. A lower limit of thelength of the break portion 22A is preferably 10 μm, more preferably is15 μm, and further preferably is 20 μm. An upper limit of the length ofthe break portion 22A is preferably 50 μm, more preferably is 40 μm, andfurther preferably is 30 μm. The preferable range is 10 μm or more and50 μm or less, and is 15 μm or more and 30 μm or less. In addition, arange where the break portion 22A is formed can be expressed, forinstance, by a dispersion of line density. Here, the dispersion of theline density is a dispersion of the total thin wire length in a unitsmall lattice, and can be defined as ±(maximum value of total wirelength−minimum value of total wire length)/average value of total wirelength/2(%). The dispersion of the line density in the range where thebreak portion 22A is formed is preferably ±15%, and more preferably is±10%.

In the above described electroconductive sheet 10 for a touch panel, thelattice 24A has an approximately rhombic shape. Here, the approximatelyrhombic shape means a parallelogram of which the diagonal lines aresubstantially perpendicular to each other. However, the shape may alsobe a polygonal shape, in addition to the approximately rhombic shape. Inaddition, the shape of one side may also be a curved shape or an arcshape in addition to a linear shape. When the shape is formed into thearc shape, two facing sides may be formed into such an arc shape as tobe outwardly convex, and the other facing sides may be formed into suchan arc shape as to be inwardly convex, for instance. In addition, theshape of each side may be such a wavy line shape that the outwardlyconvex arc shape and the inwardly convex arc shape continue. Of course,the shape of each side may be a sinusoidal curve.

Each of the first electroconductive patterns 18A has a wide portion anda narrow portion which are alternately arranged in the first direction(x-direction), and forms a so-called diamond pattern. Similarly, each ofthe first non-electroconductive patterns 20A has a wide portion and anarrow portion which are alternately arranged in the first direction(x-direction). An order of the wide portion and the narrow portion inthe first electroconductive pattern 18A becomes reverse to the order ofthe wide portion and the narrow portion in the firstnon-electroconductive pattern 20A. Incidentally, each of the firstelectroconductive patterns 18A is not limited to the above describeddiamond pattern, but may be a belt shape (stripe shape) having apredetermined width, a zigzag shape having a predetermined width, or thelike. Patterning includes an electrode shape which is formed in anexisting ITO transparent electroconductive film.

One end of each of the first electroconductive patterns 18A iselectrically connected to a first external wire 62A through a firstelectrode terminal 60A. On the other hand, the other end of each of thefirst electroconductive patterns 18A is an open end. Incidentally, theother end of each of the first electroconductive patterns 18A may beformed into a shape having a pattern shape and a terminal, which aresimilar to those of the one end, except that the other end is notelectrically connected to the external wire.

The second electroconductive sheet 12B has a second electrode pattern16B formed on one principal surface of a second transparent substrate14B (see FIG. 5A), as is illustrated in FIG. 4A, FIG. 4B and FIG. 6B.The second electrode pattern 16B is constructed of a large number oflattices formed of a metal thin wire. The second electrode pattern 16Bhas two or more second electroconductive patterns 18B which extend eachin the second direction (y-direction) and are arrayed in the firstdirection (x-direction) perpendicular to the second direction, andsecond non-electroconductive patterns 20B which electrically separateeach of the second electroconductive patterns 18B. In the secondnon-electroconductive pattern 20B, a plurality of break portions 22B areformed in places other than intersections of the metal thin wires. Eachof the second electroconductive patterns 18B is electrically separatedby the plurality of break portions 22B.

The metal thin wire which constitutes the second electrode pattern 16Bhas substantially the same line width as that of the metal thin wirewhich constitutes the first electrode pattern 16A. Incidentally, thesecond electroconductive pattern 18B and the secondnon-electroconductive pattern 20B have substantially the same linewidth, but in FIG. 6B, in order to clarify the second electroconductivepattern 18B and the second non-electroconductive pattern 20B, thepatterns are exaggeratedly illustrated so that the line width of thesecond electroconductive pattern 18B is thick and the line width of thesecond non-electroconductive pattern 20B is thin. The line width of thesecond electroconductive pattern 18B and the line width of the secondnon-electroconductive pattern 20B may be the same or may be different.The line widths of both the patterns are preferably the same. The reasonis because when the line widths are different, visibility isoccasionally aggravated.

The metal thin wire of the second electrode pattern 16B is made from thesame electroconductive material as that of the metal thin wire of thefirst electrode pattern 16A.

The second electrode pattern 16B includes a plurality of lattices 24Bwhich are constructed of the intersecting metal thin wires. The lattice24B includes an opening region which is surrounded by the metal thinwire. The lattice 24B has a lattice pitch Pb of 300 μm or more and 800μm or less, and preferably of 400 μm or more and 600 μm or less. Thelattices 24B of the second electroconductive pattern 18B and thelattices 24B of the second non-electroconductive pattern 20B havesubstantially the same size.

The lattice 24B of the second non-electroconductive pattern 20B hasbreak portions 22B in places other than intersections of the metal thinwires. All of the lattices 24B which constitute the secondnon-electroconductive pattern 20B do not need to have the break portion22B as long as the second non-electroconductive pattern 20B may achieveelectrical isolation between the adjacent second electroconductivepatterns 18B. The length of the break portion 22B is preferably 60 μm orless. A lower limit of the length of the break portion 22B is preferably10 μm, more preferably is 15 μm, and further preferably is 20 μm. Anupper limit of the length of the break portion 22B is preferably 50 μm,more preferably is 40 μm, and further preferably is 30 μm. A preferablerange is 10 μm or more and 50 μm or less, and is 15 μm or more and 30 μmor less. In addition, a range where the break portion 22B is formed canbe expressed, for instance, by a dispersion of line density. Here, thedispersion of the line density is a dispersion of the total thin wirelength in a unit small lattice, and can be defined as ±(maximum value oftotal wire length−minimum value of total wire length)/average value oftotal wire length/2(%). The dispersion of the line density in the rangewhere the break portion 22B is formed is preferably ±15%, and morepreferably is ±10%.

In the above described electroconductive sheet 10 for a touch panel, thelattice 24B has an approximately rhombic shape. Here, the approximatelyrhombic shape means a parallelogram of which the diagonal lines aresubstantially perpendicular to each other. However, the shape may alsobe a polygonal shape, in addition to the approximately rhombic shape. Inaddition, the shape of one side may also be a curved shape or an arcshape, in addition to a linear shape. When the shape of the side isformed into the arc shape, two facing sides may be formed into such anarc shape as to be outwardly convex, and the other facing sides may beformed into such an arc shape as to be inwardly convex, for instance. Inaddition, the shape of each side may be such a wavy line shape that theoutwardly convex arc shape and the inwardly convex arc shape continue.Of course, the shape of each side may be a sinusoidal curve.

Each of the second electroconductive patterns 18B has a wide portion anda narrow portion which are alternately arranged in the second direction(y-direction). Similarly, each of the second non-electroconductivepatterns 20B has a wide portion and a narrow portion which arealternately arranged in the second direction (y-direction). An order ofthe wide portion and the narrow portion in the second electroconductivepattern 18B becomes reverse to the order of the wide portion and thenarrow portion in the second non-electroconductive pattern 20B.

One end of each of the second electroconductive patterns 18B iselectrically connected to a second external wire 62B through a secondelectrode terminal 60B. On the other hand, the other end of each of thesecond electroconductive patterns 18B is an open end.

In addition, when the first electroconductive sheet 12A is stacked onthe second electroconductive sheet 12B to form the electroconductivesheet 10 for a touch panel, for instance, as is illustrated in FIG. 7,the first electrode pattern 16A is arranged so as not to overlap withthe second electrode pattern 16B. At this time, the first electrodepattern 16A and the second electrode pattern 16B are arranged so thatthe narrow portions of the first electroconductive pattern 18A face thenarrow portions of the second electroconductive pattern 18B, and thenarrow portions of the first electroconductive pattern 18A intersectswith the narrow portions of the second electroconductive pattern 18B. Asa result, a combination pattern 70 is formed by the first electrodepattern 16A and the second electrode pattern 16B. Incidentally, each ofthe line widths of the first electrode pattern 16A and the secondelectrode pattern 16B is substantially the same as the other. Inaddition, each of the sizes of the lattices 24A and the lattices 24B issubstantially the same as the other. However, in FIG. 6A and FIG. 6B, inorder to clarify a positional relationship between the first electrodepattern 16A and the second electrode pattern 16B, the line width of thefirst electrode pattern 16A is illustrated so as to be thicker than theline width of the second electrode pattern 16B.

In the combination pattern 70, small lattices are formed by the lattices24A and the lattices 24B when viewed from a top surface. Specifically,the intersections of the lattices 24A are arranged in the openingregions of the lattices 24B. Incidentally, the small lattices have alattice pitch Ps of 150 μm or more and 400 μm or less, which is a halfof the lattice pitches Pa and Pb of the lattices 24A and the lattices24B, and preferably of 200 μm or more and 300 μm or less.

The break portions 22A of the first non-electroconductive pattern 20Aare formed in places other than the intersections of the lattices 24A,and the break portions 22B of the second non-electroconductive pattern20B are formed in places other than the intersections of the lattices24B. As a result, in the combination pattern 70, the deterioration ofthe visibility, which originates in the break portion 22A and the breakportion 22B, can be prevented.

The metal thin wire of the second electroconductive pattern 18B isarranged particularly at a position facing the break portions 22A. Inaddition, the metal thin wire of the first electroconductive pattern 18Ais arranged at a position facing the break portions 22B. As a result,the metal thin wire of the second electroconductive pattern 18B masksthe break portions 22A and the metal thin wire of the firstelectroconductive pattern 18A masks the break portions 22B. Accordingly,in the combination pattern 70, the break portions 22A and the breakportions 22B become hard to be recognized when viewed from a topsurface, and the visibility can be enhanced. When enhancement ofvisibility is considered, the length of the break portions 22A and theline width of the metal thin wire of the second electroconductivepattern 18B preferably satisfy the relational expression of: linewidth×1<break portion<line width×10. Similarly, the length of the breakportions 22B and the line width of the metal thin wire of the firstelectroconductive pattern 18A preferably satisfy the relationalexpression of: line width×1<break portion<line width×10.

When this electroconductive sheet 10 for a touch panel is used as atouch panel, a protective layer (not-shown) is formed on the firstelectroconductive sheet 12A. The first external wires 62A which havebeen derived from a large number of the respective firstelectroconductive patterns 18A of the first electroconductive sheet 12A,and the second external wires 62B which have been derived from a largenumber of the respective second electroconductive patterns 18B of thesecond electroconductive sheet 12B are connected, for instance, to an ICcircuit which controls scanning.

In order to minimize the area in an outer peripheral region outside adisplay screen of a liquid crystal display device, out of theelectroconductive sheet 10 for a touch panel, it is preferable that eachconnecting portion between the first electroconductive pattern 18A andthe first external wire 62A be linearly arrayed, and each connectingportion between the second electroconductive pattern 18B and the secondexternal wire 62B be linearly arrayed.

When a finger comes in contact with the protective layer, a capacitancebetween the first electroconductive pattern 18A and the secondelectroconductive pattern 18B which face the finger changes. The ICcircuit detects the amount of this change, and calculates a position ofthe finger based on the amount of this change. This calculation isperformed between the respective first electroconductive patterns 18Aand the respective second electroconductive patterns 18B. Accordingly,even when two or more fingers simultaneously come in contact with theprotective layer, the positions of each of the fingers can be detected.

Thus, when the electroconductive sheet 10 for a touch panel is used forapplication, for instance, to a projected capacitive touch panel, aresponse speed can be increased because a surface resistance is small inthe electroconductive sheet 10 for a touch panel, and the trend ofincreasing the size of the touch panel can be promoted.

However, in a touch panel in which a conventional metal thin wire isused for electrodes, thick terminals (solid terminals) are used as theelectrode terminals 60A and 60B so as to provide highelectroconductivity. Accordingly, when a display and the touch panel areoperated in combination, the electrode terminals shield light emittedfrom the display in a sensing region (electrode pattern) of the touchpanel. Thus, a darkened portion appears in a vicinity of the electrodeterminals in the sensing region, and the display in that portionoccasionally becomes less-viewable.

Thus, the present invention has achieved the first to thirdelectroconductive sheets for a touch panel, which are described below.

(First Electroconductive Sheet for Touch Panel)

A first electroconductive sheet for a touch panel according the presentinvention is the above described electroconductive sheet 12A (12B) whichhas, on a substrate 14A, an electrode pattern 16A (16B) constructed of ametal thin wire and an electrode terminal 60A (60B) that is electricallyconnected to an end of the electrode pattern 16A (16B), wherein theelectrode pattern 16A (16B) is configured to have a transmittance of 83%or more, and when a transmittance of the electrode pattern 16A (16B) isrepresented by a %, the electrode terminal 60A (60B) is configured tohave a transmittance of (a-20)% or more and (a-3)% or less. In addition,more preferably, the transmittance of the electrode terminal 60A (60B)is in a range of (a-15)% or more and (a-3)% or less, further preferablyof (a-10) or more and (a-3) or less, and most preferably of (a-5) ormore and (a-3) or less.

In addition, the first electroconductive sheet for a touch panel ofanother aspect according the present invention is the above describedelectroconductive sheet 12A (12B) which has, on the substrate 14A, anelectrode pattern 16A (16B) constructed of the metal thin wire and anelectrode terminal 60A (60B) that is electrically connected to an end ofthe electrode pattern 16A (16B), wherein the electrode pattern 16A (16B)is configured to have an aperture ratio of 90% or more, and when theaperture ratio of the electrode pattern 16A (16B) is represented by b %,the electrode terminal 60A (60B) is configured to have an aperture ratioof (b-20)% or more and (b-0.1)% or less. In addition, more preferably,the aperture ratio is in a range of (b-10) or more and (b-0.3) or less,and further preferably of (b-5) or more and (b-0.3) or less.

FIG. 1 illustrates an example in which the electrode terminal 60A (60B)has a frame shape 64 constructed of a metal thin wire. Here, when a linewidth of the thin wire of the electrode pattern 16A (16B) is representedby A (μm), a line width B (μm) of the frame shape of the electrodeterminal 60A (60B) preferably satisfies B≧2A or B≧A+5 (μm). The linewidth a (μm) of the thin wire of the above described electrode patternis preferably 30 μm or less.

As is illustrated in FIG. 1, the electrode terminal 60A (60B) isstructured so as to have the frame shape 64 constructed of the metalthin wire, thereby a transmittance of the electrode pattern 16A (16B)can be made to be 83% or more, and when the transmittance of theelectrode pattern 16A (16B) is represented by a %, a transmittance ofthe electrode terminal 60A (60B) can be made to be (a-20)% or more and(a-3)% or less.

In addition, when the electrode terminal 60A (60B) is structured so asto have the frame shape 64 constructed of the metal thin wire, anaperture ratio of the electrode pattern 16A (16B) can be made to be 90%or more, and when the aperture ratio of the electrode pattern 16A (16B)is represented by b %, an aperture ratio of the electrode terminal 60A(60B) can be made to be (b-20)% or more and (b-0.1)% or less.

Accordingly, when the electrode terminal 60A (60B) is structured so asto be the frame shape 64 constructed of the metal thin wire, theelectrode terminal becomes hard to shield light emitted from the displayin the sensing region (electrode pattern) of the touch panel, which isdifferent from the conventional thick terminal (solid terminal). Thus, adarkened portion does not appear in the vicinity of the electrodeterminal in the sensing region. Accordingly, visibility is not impairedin the vicinity of the electrode terminal in the sensing region.

FIG. 2 illustrates an example in which the electrode terminal 60A (60B)has a mesh shape 66 formed of lattices 68 constructed of a metal thinwire. Here, a pitch of the mesh shape 66 of the electrode terminal 60A(60B) is preferably denser than the pitch of the electrode pattern 16A(16B), more preferably is not larger than ¾ of the pitch of theelectrode pattern 16A (16B), further preferably is not larger than ⅔thereof, and still further preferably is ½ thereof. When the pitchhaving the mesh shape of the electrode terminal is made smaller thanthat of the electrode pattern, electric characteristics of the electrodeterminal can be enhanced and the stability of signal detection can bemaintained. The specific pitch of the mesh shape 66 of the electrodeterminal 60A (60B) is 50 μm or more and 300 μm or less, and morepreferably is 50 μm or more and 250 μm or less. Incidentally, the pitchof the electrode pattern 16A (16B) is a value approximately equal to thelength of one side of the lattice 24A (24B).

As is illustrated in FIG. 2, the electrode terminal 60A (60B) isstructured so as to have a mesh shape 66 formed of the lattices 68constructed of the metal thin wire, thereby a transmittance of theelectrode pattern 16A (16B) can be made to be 83% or more, and when thetransmittance of the electrode pattern 16A (16B) is represented by a %,a transmittance of the electrode terminal 60A (60B) can be made to be(a-20)% or more and (a-3)% or less.

In addition, when the electrode terminal 60A (60B) is structured so asto have the mesh shape 66 formed of the lattices 68 constructed of themetal thin wire, an aperture ratio of the electrode pattern 16A (16B)can be made to be 90% or more, and when the aperture ratio of theelectrode pattern 16A (16B) is represented by b %, an aperture ratio ofthe electrode terminal 60A (60B) can be made to be (b-20)% or more and(b-0.1)% or less.

Accordingly, when the electrode terminal 60A (60B) is structured so asto have the mesh shape 66 constructed of the metal thin wire, theelectrode terminal resists shielding light emitted from the display inthe sensing region (electrode pattern) of the touch panel, andaccordingly a darkened portion does not appear in the vicinity of theelectrode terminal in the sensing region, which is different from theconventional thick terminal (solid terminal). Accordingly, visibility isnot impaired in the vicinity of the electrode terminal in the sensingregion.

FIG. 3 illustrates an example in which the electrode terminal 60A (60B)is formed of: the frame shape 64 constructed of the metal thin wire; andthe mesh shape 66 formed of the lattices 68 constructed of the metalthin wire.

As is illustrated in FIG. 3, the electrode terminal 60A (60B) is formedof: the frame shape 64 constructed of the metal thin wire; and the meshshape 66 formed of the lattices 68 constructed of the metal thin wire,thereby a transmittance of the electrode pattern 16A (16B) can be madeto be 83% or more, and when the transmittance of the electrode pattern16A (16B) is represented by a %, the transmittance of the electrodeterminal 60A (60B) can be made to be (a-20)% or more and (a-3)% or less.

In addition, when the electrode terminal 60A (60B) is formed of: theframe shape 64 constructed of the metal thin wire; and the mesh shape 66formed of the lattices 68 constructed of the metal thin wire, anaperture ratio of the electrode pattern 16A (16B) can be made to be 90%or more, and when the aperture ratio of the electrode pattern 16A (16B)is represented by b %, an aperture ratio of the electrode terminal 60A(60B) can be made to be (b-20)% or more and (b-0.1)% or less.

Accordingly, when the electrode terminal 60A (60B) is formed of: theframe shape 64 constructed of the metal thin wire; and the mesh shape 66formed of the lattices 68 constructed of the metal thin wire, theelectrode terminal resists shielding light emitted from the display in asensing region (electrode pattern) of the touch panel, and accordingly adarkened portion does not appear in the vicinity of the electrodeterminal in the sensing region, which is different from the conventionalthick terminal (solid terminal). Accordingly, visibility is not impairedin the vicinity of the electrode terminal in the sensing region.

Incidentally, in the mesh shape 66 in FIG. 2 and FIG. 3, the lattice 68has an approximately rhombic shape. Here, the approximately rhombicshape means a parallelogram of which the diagonal lines aresubstantially perpendicular to each other. However, the shape may alsobe a polygonal shape, in addition to the approximately rhombic shape. Inaddition, the shape of one side may also be a curved shape or an arcshape, in addition to a linear shape. When the shape is formed into thearc shape, two facing sides may be formed into such an arc shape as tobe outwardly convex, and the other facing sides may be formed into suchan arc shape as to be inwardly convex, for instance. In addition, theshape of each side may be such a wavy line shape that the outwardlyconvex arc shape and the inwardly convex arc shape continue. Of course,the shape of each side may be a sinusoidal curve.

In the electrode terminal 60A (60B) according to the present invention,a resistance between a portion which is electrically connected to theelectrode pattern and the external wire 62A (62B) is preferably in arange of 1 to 100Ω. In addition, when the electrode terminal 60A (60B)includes the mesh shape 66 as is illustrated in FIG. 2 and FIG. 3, asurface resistance value of the electrode terminal 60A (60B) ispreferably in a range of 4 Ω/sq. or more and 80 Ω/sq. or less, andfurther preferably is in a range of 10 Ω/sq. or more and 40 Ω/sq. orless.

Incidentally, the aperture ratio is a ratio of a translucent portionexcept for the metal thin wire occupying in the whole in the electrodeterminal 60A (60B). For instance, an aperture ratio of the lattice 68 is90%, the lattice 68 which has a square shape with a line width of 15 μmand a pitch of 300 μm.

(Second Electroconductive Sheet for Touch Panel)

A second electroconductive sheet for a touch panel according the presentinvention is the above described electroconductive sheet 12A (12B) whichhas, on a substrate 14A, an electrode pattern 16A (16B) constructed of ametal thin wire and an electrode terminal 60A (60B) that is electricallyconnected to an end of the electrode pattern 16A (16B), wherein theelectrode terminal 60A (60B) is configured to include a frame shape 64constructed of a metal thin wire.

FIG. 1 illustrates an example in which the electrode terminal 60A (60B)is a frame shape 64 constructed of a metal thin wire.

Here, when a line width of the thin wire of the electrode pattern 16A(16B) is represented by A (μm), a line width B (μm) of the frame shapeof the electrode terminal 60A (60B) preferably satisfies B≧2A or B≧A+5(μm). The line width B (μm) of the frame shape is in a range, morepreferably, of 50 μm≧B≧10 μm, and further preferably of 30 μm≧B≧15 μm.In addition, the frame shape 64 is approximately a rectangular shape,and the breadth is approximately the same length as the maximum breadthof the electrode pattern, but may also be smaller than the maximumbreadth of the electrode pattern. Incidentally, when the breadth isextremely smaller than the maximum breadth of the electrode pattern, anelectric resistance increases. Accordingly, the breadth is preferablynot smaller than ⅓ of the maximum breadth of the electrode pattern, andmore preferably is not smaller than ½ thereof.

As is illustrated in FIG. 1, the electrode terminal 60A (60B) isstructured so as to be the frame shape 64 constructed of the metal thinwire, thereby the electrode terminal resists shielding light emittedfrom the display in the sensing region (electrode pattern) of the touchpanel, and accordingly a darkened portion does not appear in thevicinity of the electrode terminal in the sensing region, which isdifferent from the conventional thick terminal (solid terminal).Accordingly, visibility is not impaired in the vicinity of the electrodeterminal in the sensing region. In addition, when such a shape isadopted, there are also such effects that an amount of components to beused can be reduced without increasing a noise of an electric signal,and a production cost of an electroconductive film can be reduced.

FIG. 3 illustrates an example in which the electrode terminal 60A (60B)is formed of: the frame shape 64 constructed of the metal thin wire; andthe mesh shape 66 formed of the lattices 68 constructed of the metalthin wire. Here, the pitch of the mesh shape 66 of the electrodeterminal 60A (60B) is preferably denser than the pitch of the electrodepattern 16A (16B), more preferably is not larger than ¾ of the pitch ofthe electrode pattern 16A (16B), further preferably is not larger than ⅔thereof, and still further preferably is ½ thereof. When the pitchhaving the mesh shape of the electrode terminal is made smaller thanthat of the electrode pattern, electric characteristics of the electrodeterminal can be enhanced and the stability of signal detection can bemaintained. The specific pitch of the mesh shape 66 of the electrodeterminal 60A (60B) is 50 μm or more and 300 μm or less, and morepreferably is 50 μm or more and 250 μm or less. Incidentally, the pitchof the electrode pattern 16A (16B) is a value approximately equal to thelength of one side of the lattice 24A (24B).

As is illustrated in FIG. 3, the electrode terminal 60A (60B) is formedof: the frame shape 64 constructed of the metal thin wire; and the meshshape 66 formed of the lattices 68 constructed of the metal thin wire,thereby the electrode terminal resists shielding light emitted from thedisplay in a sensing region (electrode pattern) of the touch panel, andaccordingly a darkened portion does not appear in the vicinity of theelectrode terminal in the sensing region, which is different from theconventional thick terminal (solid terminal). Accordingly, visibility isnot impaired in the vicinity of the electrode terminal in the sensingregion.

Incidentally, in the mesh shape 66 in FIG. 3, the lattice 68 has anapproximately rhombic shape. Here, the approximately rhombic shape meansa parallelogram of which the diagonal lines are substantiallyperpendicular to each other. However, the shape may also be a polygonalshape, in addition to the approximately rhombic shape. In addition, theshape of one side may also be a curved shape or an arc shape, inaddition to a linear shape. When the shape is formed into the arc shape,two facing sides may be formed into such an arc shape as to be outwardlyconvex, and the other facing sides may be formed into such an arc shapeas to be inwardly convex, for instance. In addition, the shape of eachside may be such a wavy line shape that the outwardly convex arc shapeand the inwardly convex arc shape continue. Of course, the shape of eachside may be a sinusoidal curve.

In the electrode terminal 60A (60B) according to the present invention,a resistance between a portion which is electrically connected to theelectrode pattern and the external wire 62A (62B) is preferably in arange of 1 to 100Ω. In addition, when the electrode terminal 60A (60B)includes the mesh shape 66 as is illustrated in FIG. 3, a surfaceresistance value of the electrode terminal 60A (60B) is preferably in arange of 4 Ω/sq. or more and 80 Ω/sq. or less, and further preferably isin a range of 10 Ω/sq. or more and 40 Ω/sq. or less.

Incidentally, the aperture ratio is a ratio of a translucent portionexcept for the metal thin wire occupying in the whole in the electrodeterminal 60A (60B), and for instance, an aperture ratio of the lattice68 is 90%, the lattice 68 which has a square shape with a line width of15 μm and a pitch of 300 μm.

In addition, in the present invention, in the case of FIG. 3, it ispreferable that a transmittance of the electrode pattern 16A (16B) be83% or more, and that when the transmittance of the electrode pattern16A (16B) is represented by a %, a transmittance of the electrodeterminal 60A (60B) be (a-20)% or more and (a-3)% or less.

Furthermore, in the present invention, in the case of FIG. 3, it ispreferable that an aperture ratio of the electrode pattern 16A (16B) be90% or more, and that when the aperture ratio of the electrode pattern16A (16B) is represented by b %, an aperture ratio of the electrodeterminal 60A (60B) be (b-20)% or more and (b-0.1)% or less.Incidentally, the aperture ratio here is a ratio of a translucentportion except for the metal thin wire occupying in the whole in theelectrode terminal 60A (60B). For instance, an aperture ratio of thelattice 68 is 90%, the lattice 68 which has a square shape with a linewidth of 15 μm and a pitch of 300 μm.

(Third Electroconductive Sheet for Touch Panel)

A third electroconductive sheet for a touch panel according the presentinvention is the above described electroconductive sheet 12A (12B) whichhas, on a substrate 14A, an electrode pattern 16A (16B) constructed of ametal thin wire and an electrode terminal 60A (60B) that is electricallyconnected to an end of the electrode pattern 16A (16B), wherein theelectrode terminal 60A (60B) is configured to include a mesh shape 66formed of lattices 68 constructed of a metal thin wire.

FIG. 2 illustrates an example in which the electrode terminal 60A (60B)is a mesh shape 66 formed of lattices 68 constructed of a metal thinwire.

Here, the pitch of the mesh shape 66 of the electrode terminal 60A (60B)is preferably denser than the pitch of the electrode pattern 16A (16B),more preferably is not larger than ¾ of the pitch of the electrodepattern 16A (16B), further preferably is not larger than ⅔ thereof, andstill further preferably is ½ thereof. When the pitch having the meshshape of the electrode terminal is made smaller than that of theelectrode pattern, electric characteristics of the electrode terminalcan be enhanced and the stability of signal detection can be maintained.The specific pitch of the mesh shape 66 of the electrode terminal 60A(60B) is 50 μm or more and 300 μm or less, and more preferably is 50 μmor more and 250 μm or less. Incidentally, the pitch of the electrodepattern 16A (16B) is a value approximately equal to the length of oneside of the lattice 24A (24B).

As is illustrated in FIG. 3, the electrode terminal 60A (60B) isstructured so as to have a mesh shape 66 formed of the lattices 68constructed of the metal thin wire, thereby the electrode terminalresists shielding light emitted from the display in the sensing region(electrode pattern) of the touch panel, and accordingly a darkenedportion does not appear in the vicinity of the electrode terminal in thesensing region, which is different from the conventional thick terminal(solid terminal). Accordingly, visibility is not impaired in thevicinity of the electrode terminal in the sensing region.

FIG. 3 illustrates the electrode terminal 60A (60B) that has the meshshape 66 formed of the lattices 68 constructed of the metal thin wireillustrated in FIG. 2, further has a frame shape 64 constructed of ametal thin wire provided on an outer frame of the mesh shape 66 formedof the lattices 68 of the electrode terminal. Specifically, FIG. 3illustrates the electrode terminal 60A (60B) which is formed of: theframe shape 64 constructed of the metal thin wire; and the mesh shape 66formed of the lattices 68 constructed of the metal thin wire.

Here, when a line width of a thin wire of the electrode pattern 16A(16B) is represented by A (μm), a line width B (μm) of the frame shape64 of the electrode terminal 60A (60B) preferably satisfies B≧2A orB≧A+5 (μm).

As is illustrated in FIG. 3, the electrode terminal 60A (60B) is formedof: the frame shape 64 constructed of the metal thin wire; and the meshshape 66 formed of the lattices 68 constructed of the metal thin wire,thereby light can be prevented from being irregularly reflected on theelectrode terminal in a sensing region (electrode pattern) of the touchpanel, and accordingly a darkened portion can be prevented fromappearing in the vicinity of the electrode terminal in the sensingregion, which is different from the conventional thick terminal (solidterminal).

Incidentally, in the mesh shape 66 in FIG. 2 and FIG. 3, the lattice 68has an approximately rhombic shape. Here, the approximately rhombicshape means a parallelogram of which the diagonal lines aresubstantially perpendicular to each other.

In the electrode terminal 60A (60B) according to the present invention,a resistance between a portion which is electrically connected to theelectrode pattern and the external wire 62A (62B) is preferably in arange of 1 to 100 Ω. In addition, in the electrode terminal 60A (60B) asis illustrated in FIG. 2 and FIG. 3, a surface resistance value of theelectrode terminal 60A (60B) is preferably in a range of 4 Ω/sq. or moreand 80 Ω/sq. or less, and further preferably is in a range of 10 Ω/sq.or more and 40 Ω/sq. or less.

In addition, in the present invention, it is preferable that atransmittance of the electrode pattern 16A (16B) be 83% or more, andthat when the transmittance of the electrode pattern 16A (16B) isrepresented by a %, the transmittance of the electrode terminal 60A(60B) is (a-20)% or more and (a-3)% or less.

Furthermore, in the present invention, it is preferable that an apertureratio of the electrode pattern 16A (16B) be 90% or more, and that whenthe aperture ratio of the electrode pattern 16A (16B) is represented byb %, an aperture ratio of the electrode terminal 60A (60B) be (b-20)% ormore and (b-0.1)% or less. Incidentally, the aperture ratio here is aratio of a translucent portion except for the metal thin wire occupyingin the whole in the electrode terminal 60A (60B), and for instance, anaperture ratio of the lattice 68 is 90%, the lattice 68 which has asquare shape with a line width of 15 μm and a pitch of 300 μm.

As has been described above, the present invention can prevent a portionwhich becomes dark from appearing in the vicinity of the electrodeterminal in the sensing region. Further, as another effect, the presentinvention also has an effect that the metal thin wire in the vicinity ofthe electrode terminal in the sensing region can be prevented fromresulting in being thicker than an intended line width, when theelectroconductive sheet 12A (12B) is produced by a production methodusing light exposure, which is described below.

Because the conventional electrode terminal is a thick terminal (solidterminal) so as to have high electroconductivity, the portion whichbecomes the electrode terminal is irradiated with a large quantity oflight by light exposure. There have been problems that a line width ofan electrode pattern is extremely small and the light is transferredalso to a portion which becomes the electrode pattern in the vicinity ofthe electrode terminal, and the metal thin wire in the vicinity of theelectrode terminal becomes thicker than the intended line width.

Specifically, when a transmittance or an aperture ratio of the electrodeterminal 60A (60B) is set as in the present invention, it does not occurthat the portion which becomes the electrode terminal is irradiated witha large quantity of light by light exposure, and thus, it can beprevented that the metal thin wire in the vicinity of the electrodeterminal in the sensing region results in being thicker than theintended line width.

Incidentally, when a user touches and operates with his finger the touchpanel in which the electroconductive sheet according to the presentinvention is used, a response speed is quick and detection sensitivityis excellent. In addition, even when a user touches and operates withhis fingers the touch panel at two or more points, similarly, a goodresult is obtained, and the touch panel can cope with multitouch.

Next, a method for producing a first electroconductive sheet 12A and asecond electroconductive sheet 12B is described below.

When the first electroconductive sheet 12A and the secondelectroconductive sheet 12B are produced, it is acceptable, forinstance, to expose photosensitive materials which have layers of anemulsion containing a photosensitive silver halide salt formed on afirst transparent substrate 14A and a second transparent substrate 14Bto light, to subject the transparent substrates to developmenttreatment, thereby to form a metal silver portion (metal thin wire) andan optically transparent portion (opening region) on an exposed portionand an unexposed portion, and to form a first electrode pattern 16A anda second electrode pattern 16B. Incidentally, it is also acceptable tosubject the metal silver portion further to physical development and/orplating treatment, and thereby make the metal silver portion carry anelectroconductive metal.

Alternatively, it is acceptable to expose photoresist layers formed oncopper foils which have been formed on the first transparent substrate14A and the second transparent substrate 14B, to light, to subject thelayers to development treatment to form resist patterns, to etch thecopper foils which are exposed from the resist patterns, and thereby toform the first electrode pattern 16A and the second electrode pattern16B.

Alternatively, it is also acceptable to print a paste containing metalfine particles on the first transparent substrate 14A and the secondtransparent substrate 14B, and plate a metal on the paste to therebyform the first electrode pattern 16A and the second electrode pattern16B.

When the first electrode pattern 16A and the second electrode pattern16B are formed by the above described two production methods by lightexposure, the present invention can also achieve an effect that a metalthin wire in the vicinity of an electrode terminal in a sensing regioncan be prevented from being thicker than an intended line width.

It is also acceptable to form the first electrode pattern 16A and thesecond electrode pattern 16B on the first transparent substrate 14A andthe second transparent substrate 14B by printing, with a screen printingplate or a gravure printing plate. Alternatively, it is also acceptableto form the first electrode pattern 16A and the second electrode pattern16B on the first transparent substrate 14A and the second transparentsubstrate 14B, with an ink-jet technique.

As is illustrated in FIG. 5B, in the case where the first electrodepattern 16A is formed on one principal surface of the first transparentsubstrate 14A, and the second electrode pattern 16B is formed on theother principal surface of the first transparent substrate 14A, if amethod of firstly exposing the one principal surface to light and thenexposing the other principal surface to light is adopted according to ausual production method, there is the case where the first electrodepattern 16A and the second electrode pattern 16B which have desiredpatterns cannot be obtained.

Then, a production method which is described below can be preferablyadopted.

Specifically, layers of a photosensitive silver halide emulsion formedon both sides of the first transparent substrate 14A are collectivelyexposed to light to form the first electrode pattern 16A on the oneprincipal surface of the first transparent substrate 14A and form thesecond electrode pattern 16B on the other principal surface of the firsttransparent substrate 14A.

Specific examples of this production method are described below.

Firstly, a long photosensitive material is produced. The photosensitivematerial has a first transparent substrate 14A, a layer of aphotosensitive silver halide emulsion (hereinafter referred to as firstphotosensitive layer) formed on one principal surface of the firsttransparent substrate 14A, and a layer of a photosensitive silver halideemulsion (hereinafter referred to as second photosensitive layer) formedon the other principal surface of the first transparent substrate 14A.

Next, the photosensitive material is exposed to light. In this exposuretreatment, the first photosensitive layer is subjected to first exposuretreatment which irradiates the first transparent substrate 14A withlight to expose the first photosensitive layer to light along a firstexposure pattern, and the second photosensitive layer is subjected tosecond exposure treatment which irradiates the first transparentsubstrate 14A with light to expose the second photosensitive layer tolight along a second exposure pattern (simultaneous light exposure ofboth sides).

For instance, while the long photosensitive material is transported inone direction, the first photosensitive layer is irradiated with firstlight (parallel light) through a first photomask, and the secondphotosensitive layer is irradiated with second light (parallel light)through a second photomask. The first light can be obtained by aprocedure of converting the light which has been emitted from a firstlight source into the parallel light with a first collimating lens onthe way, and the second light can be obtained by the procedure ofconverting the light which has been emitted from a second light sourceinto the parallel light with a second collimating lens on the way.

In the above description, the case has been described where two lightsources (first light source and second light source) are used, but alight which has been emitted from one light source may be divided intofirst light and second light through an optical system, and mayirradiate the first photosensitive layer and the second photosensitivelayer as the first light and the second light.

Subsequently, the photosensitive material after light exposure issubjected to the development treatment. Thereby, an electroconductivesheet 10 for a touch panel is produced, for instance, as is illustratedin FIG. 4B. The electroconductive sheet 10 for a touch panel has thefirst transparent substrate 14A, the first electrode pattern 16A alongthe first exposure pattern, which has been formed on one principalsurface of the first transparent substrate 14A, and the second electrodepattern 16B along the second exposure pattern, which has been formed onthe other principal surface of the first transparent substrate 14A.Incidentally, light exposure time and developing time for the firstphotosensitive layer and the second photosensitive layer variously varydepending on types of the first light source and the second lightsource, types of a developing solution and the like. Accordingly,preferable ranges of numerical values cannot be generally determined,but the light exposure time and the developing time are adjusted so thata development ratio becomes 100%.

In the production method according to the present embodiment, in thefirst exposure treatment, the first photomask is, for instance, arrangedto be brought into close contact with the first photosensitive layer,and the first photosensitive layer is exposed to light by beingirradiated with the first light emitted from the first light sourcearranged so as to face the first photomask toward the first photomask.The first photomask is constructed of a glass substrate formed of atransparent soda glass, and a mask pattern (first exposure pattern)formed on the glass substrate. Accordingly, by this first exposuretreatment, a portion along the first exposure pattern which is formed onthe first photomask, out of the first photosensitive layer, is exposedto light. A gap of about 2 nm or more and 10 μm or less may be providedbetween the first photosensitive layer and the first photomask 146 a.

Similarly, in the second exposure treatment, the second photomask is,for instance, arranged to be brought into close contact with the secondphotosensitive layer, and the second photosensitive layer is exposed tolight by being irradiated with the second light emitted from the secondlight source arranged so as to face the second photomask toward thesecond photomask. The second photomask is constructed of a glasssubstrate formed of a transparent soda glass, and a mask pattern (secondexposure pattern) formed on the glass substrate, similarly to the firstphotomask. Accordingly, by this second exposure treatment, a portionalong the second exposure pattern which is formed on the secondphotomask, out of the second photosensitive layer, is exposed to light.In this case, a gap of about 2 μm or more and 10 μm or less may beprovided between the second photosensitive layer and the secondphotomask.

In the first exposure treatment and the second exposure treatment, thetiming of the emission of the first light from the first light sourceand the timing of the emission of the second light from the second lightsource may be controlled to be the same or to be different. If thetimings are the same, the first photosensitive layer and the secondphotosensitive layer can be simultaneously exposed to light in oneexposure treatment, and the treatment period of time can be shortened.

Next, a method is mainly described that uses a photographic sensitivematerial of silver halide, which is a particularly preferable aspect, inthe first electroconductive sheet 12A and the second electroconductivesheet 12B according to the present embodiment.

The method for producing the first electroconductive sheet 12A and thesecond electroconductive sheet 12B according to the present embodimentincludes three following modes according to the forms of thephotosensitive material and development treatment.

(1) An aspect of subjecting a monochrome photosensitive material of aphotosensitive silver halide, which does not contain a physicaldevelopment nucleus, to chemical development or thermal development,thereby forming a metal silver portion on the photosensitive material.

(2) An aspect of subjecting a monochrome photosensitive material of aphotosensitive silver halide, which contains the physical developmentnucleus in a layer of a silver halide emulsion, to dissolution physicaldevelopment, thereby forming a metal silver portion on thephotosensitive material.

(3) An aspect of overlapping a monochrome photosensitive material of aphotosensitive silver halide, which does not contain the physicaldevelopment nucleus, with an image-receiving sheet having anon-photosensitive layer that contains the physical development nucleus,and subjecting the sheet to diffusion transfer development, therebyforming a metal silver portion on the non-photosensitive image-receivingsheet.

The above described aspect (1) is an integrated monochrome developmenttype, and a translucent electroconductive film such as an opticallytransparent electroconductive film is formed on the photosensitivematerial. The developed silver to be obtained is chemically developedsilver or thermally developed silver, and is highly active in asubsequent plating or physical development process, in a point of beinga filament having a high specific surface.

In the above described aspect (2), silver halide particles around theperiphery of the physical development nuclei are dissolved and aredeposited on the development nuclei, in the exposed portion, and therebythe translucent electroconductive film such as the optically transparentelectroconductive film is formed on the photosensitive material.

This is also an integrated monochrome development type. The developmentaction is deposition onto the physical development nucleus, andaccordingly the developed silver is highly active, but has a sphericalshape which has a small specific surface.

In the above described aspect (3), silver halide particles are dissolvedin an unexposed portion, and diffuse, and then are deposited ondevelopment nuclei on the image-receiving sheet, and thereby thetranslucent electroconductive film such as the optically transparentelectroconductive film is formed on the image-receiving sheet. Theaspect is a so-called separate type and is an aspect in which theimage-receiving sheet is separated from the photosensitive material andis used.

Any aspect can select any development of negative type developmenttreatment and reverse development treatment (in the case of thediffusion transfer method, the negative type development treatment isenabled when an autopositive type photosensitive material is used as aphotosensitive material).

Here, structures of each layer of the first electroconductive sheet 12Aand the second electroconductive sheet 12B according to the presentembodiment are described in detail below.

[First Transparent Substrate 14A and Second Transparent Substrate 14B]

Materials of the first transparent substrate 14A and the secondtransparent substrate 14B include a plastic film, a plastic sheet and aglass plate. In particular, PET is preferable from the viewpoint ofoptical transparency, processability and the like.

[Layer of Silver Salt Emulsion]

A layer of a silver salt emulsion which forms the first electrodepattern 16A of the first electroconductive sheet 12A and the secondelectrode pattern 16B of the second electroconductive sheet 12B containsan additive such as a solvent and a dye, in addition to a silver saltand a binder.

The silver salt which is used in the present embodiment includes aninorganic silver salt such as a silver halide, and an organic silversalt such as silver acetate. In the present embodiment, it is preferableto use the silver halide which is excellent in characteristics as aphotosensor.

The application amount of silver (amount of silver salt to be applied)in the layer of the silver salt emulsion is preferably 1 g/m² or moreand 30 g/m² or less in terms of silver (converted into silver), morepreferably is 1 g/m² or more and 25 g/m² or less, and further preferablyis 5 g/m² or more and 20 g/m² or less. When the electroconductive sheet10 for a touch panel is produced according to this application amount ofsilver in the above described range, a desired surface resistance can beobtained.

Binders which are used in the present embodiment include, for instance,gelatin, polyvinyl alcohol (PVA), polyvinylpyrrolidone (PVP), apolysaccharide such as starch, cellulose and a derivative thereof,polyethylene oxide, polyvinylamine, chitosan, polylysine, a polyacrylicacid, a polyalginic acid, a polyhyaluronic acid and a carboxycellulose.These binders have properties of neutrality, anionic properties, orcationic properties according to ionic properties of a functional group.

A content of the binder contained in the layer of the silver saltemulsion in the present embodiment is not limited in particular, and canbe appropriately determined in a range of being capable of exertingdispersibility and adhesiveness. The content of the binder contained inthe layer of the silver salt emulsion is preferably ¼ or more by avolume ratio of silver/binder, and more preferably is ½ or more. Thevolume ratio of silver/binder is preferably 100/1 or less, and morepreferably is 50/1 or less. In addition, the volume ratio ofsilver/binder is further preferably 1/1 or more and 4/1 or less. Thevolume ratio of silver/binder is most preferably 1/1 to 3/1. When thevolume ratio of silver/binder in the layer of the silver salt emulsionis set in this range, an electroconductive sheet for a touch panel canbe obtained, which reduces the variation of resistance values and has auniform surface resistance, even in the case where the applicationamount of silver has been adjusted. Incidentally, the volume ratio ofsilver/binder can be determined by converting the amount of the silverhalide/the amount of the binder (weight ratio) in the raw material intothe amount of silver/the amount of the binder (weight ratio), andfurther by converting the amount of silver/the amount of the binder(weight ratio) into the amount of silver/the amount of the binder(volume ratio).

<Solvent>

A solvent to be used for forming the layer of the silver salt emulsionis not limited in particular, but includes, for instance, water, anorganic solvent (for instance, alcohols such as methanol, ketones suchas acetone, amides such as formamide, sulfoxides such asdimethylsulfoxide, esters such as ethyl acetate, ethers and the like),an ionic liquid, and a mixed solvent thereof.

A content of the solvent to be used in the layer of the silver saltemulsion according to the present embodiment is in a range of 30 to 90mass % with respect to the total mass of the silver salt, the binder andthe like contained in the layer of the silver salt emulsion, andpreferably is in a range of 50 to 80 mass %.

<Other Additives>

Various additives to be used in the present embodiment are not limitedin particular, and well-known additives can be preferably used.

[Other Layer Structures]

A not-shown protective layer may be provided on the layer of the silversalt emulsion. A “protective layer” in the present embodiment means alayer formed of a binder such as gelatin and a polymer, and is formed onthe layer of the silver salt emulsion having photosensitivity so as toexert an effect of preventing scratches and improving dynamiccharacteristics. The thickness is preferably 0.5 μm or less. A method ofapplying the protective layer and a method of forming the protectivelayer are not limited in particular, and a well-known application methodand a well-known forming method can be appropriately selected. Inaddition, an undercoat layer, for instance, can also be provided underthe layer of the silver salt emulsion.

Next, each step of a method for producing the first electroconductivesheet 12A and the second electroconductive sheet 12B is described below.

[Light Exposure]

The present embodiment includes the case where the first electrodepattern 16A and the second electrode pattern 16B are formed by aprinting method, but except for the printing method, the first electrodepattern 16A and the second electrode pattern 16B are formed by lightexposure, development and the like. Specifically, a photosensitivematerial having a silver salt containing layer or a photosensitivematerial having a photopolymer for photolithography applied thereon, anyof which is provided on the first transparent substrate 14A and thesecond transparent substrate 14B, is exposed to light.

The light exposure can be conducted with the use of an electromagneticwave. The electromagnetic wave includes, for instance, light such asvisible light and ultraviolet light, and radioactive rays such asX-rays. Furthermore, a light source having a wavelength distribution maybe used for the light exposure, and a light source having a particularwavelength may be used.

As for the light exposure method, a method through a glass mask and apattern exposure method by laser drawing are preferable.

[Development Treatment]

In the present embodiment, after having been exposed to light, the layerof the emulsion is further subjected to development treatment. Thedevelopment treatment can employ a technology of usual developmenttreatment, which is used for a silver salt photographic film, aphotographic printing paper, a film for print plate-making, an emulsionmask for a photomask and the like.

The development treatment in the present embodiment can include a fixingtreatment which is conducted for the purpose of removing a silver saltin an unexposed portion and stabilizing the unexposed portion. Thefixing treatment according to the present invention can employ atechnology of fixing treatment, which is used for the silver saltphotographic film, the photographic printing paper, the film for printplate-making, the emulsion mask for the photomask and the like.

A photosensitive material which has been subjected to the developmentand fixing treatments is preferably subjected to film hardeningtreatment, washing treatment and stabilizing treatment.

The mass of the metal silver contained in the exposed portion after thedevelopment treatment is preferably a content by percentage of 50 mass %or more with respect to the mass of the silver contained in the exposedportion before the light exposure, and further preferably of 80 mass %or more. It is preferable that the mass of the silver contained in theexposed portion be 50 mass % or more with respect to the mass of thesilver contained in the exposed portion before the light exposure, inorder that high electroconductivity can be obtained.

The electroconductive sheet is obtained through the above describedsteps. A surface resistance of the obtained electroconductive sheet ispreferably 100 Ω/sq. or less, more preferably is 80 Ω/sq. or less,further preferably is 60 Ω/sq. or less, and still further preferably is40 Ω/sq. or less. The lower the lower limit of the surface resistanceis, the better the performance is. However, the lower limit is generallysufficient if being 0.01 Ω/sq., and even if the lower limit is 0.1 Ω/sq.or 1 Ω/sq., the electroconductive sheet is usable though depending onthe application.

When the surface resistance is adjusted to such a range, even in such alarge-sized touch panel having an area of 10 cm×10 cm or more, theposition can be detected. In addition, the electroconductive sheet afterthe development treatment may be further subjected to treatment forenhancing electroconductivity such as calendar treatment and vaportreatment. The surface resistance can be adjusted to a desired surfaceresistance by the calendar treatment.

[Physical Development and Plating Treatment]

In the present embodiment, a physical development and/or a platingtreatment may be conducted for making the above described metal silverportion carry electroconductive metal particles, for the purpose ofenhancing the electroconductivity of the metal silver portion which hasbeen formed by the above described light exposure and developmenttreatment. In the present invention, it is acceptable to make the metalsilver portion carry electroconductive metal particles by only any oneof the physical development and the plating treatment, and it is alsoacceptable to make the metal silver portion carry the electroconductivemetal particles by the physical development and the plating treatment incombination. Incidentally, a metal silver portion which has beensubjected to the physical development and/or the plating treatment isalso referred to as “electroconductive metal portion”.

[Oxidation Treatment]

In the present embodiment, the metal silver portion after thedevelopment treatment, and the electroconductive metal portion formed bythe physical development and/or the plating treatment are preferablysubjected to oxidation treatment. By performing the oxidation treatment,when, for instance, a metal slightly deposits on an opticallytransparent portion, the metal can be removed and the transparency ofthe optically transparent portion can be made approximately 100%.

[Electrode Pattern]

A line width of the metal thin wire of the first electrode pattern 16Aand the second electrode pattern 16B according to the present embodimentcan be selected from 30 μm or less, but when the first electrode pattern16A and the second electrode pattern 16B are used as materials of atouch panel, a lower limit of the line width of the metal thin wire ispreferably 0.7 μm, more preferably is 1 μm, and further preferably is 2μm. An upper limit of the line width of the metal thin wire ispreferably 15 μm, more preferably is 9 μm, and further preferably is 7μm.

A conventional electrode terminal employs a thick terminal (solidterminal) so as to have high electroconductivity, and a portion whichbecomes an electrode terminal by light exposure is irradiated with alarge quantity of light. The line width of the electrode pattern isextremely small as in the above description, and is occasionallyaffected by the large quantity of light. When the line width is 9 μm orless and further is 7 μm or less, in particular, the influence becomesremarkable, and there has been a problem that the metal thin wire in thevicinity of the electrode terminal becomes thicker than an intended linewidth.

A line space (lattice pitch) is preferably 100 μm or more and 400 μm orless, and further preferably is 200 μm or more and 300 μm or less. Inaddition, the metal thin wire may have a portion wider than 200 μm, forthe purpose of ground connection and the like.

[Optically Transparent Portion]

An “optically transparent portion” in the present embodiment means aportion having translucency, which excludes the first electrode pattern16A and the second electrode pattern 16B out of the firstelectroconductive sheet 12A and the second electroconductive sheet 12B.As for transmittance in the optically transparent portion, thetransmittance is 83% or more as has been described above, which isrepresented by a minimum value of transmittance in a wavelength regionof 380 to 780 nm and excludes the contribution of optical absorption andreflection in the first transparent substrate 14A and the secondtransparent substrate 14B. The minimum value of transmittance ispreferably 85% or more, is further preferably 90% or more, is furthermore preferably 93% or more, and is most preferably 99% or more.

[First Electroconductive Sheet 12A and Second Electroconductive Sheet12B]

Thicknesses of the first transparent substrate 14A and the secondtransparent substrate 14B in the first electroconductive sheet 12A andthe second electroconductive sheet 12B according to the presentembodiment are each preferably 5 μm or more and 350 μm or less, andfurther preferably are 30 μm or more and 150 μm or less. If thethickness is in the range of 5 μm or more and 350 μm or less, a desiredtransmittance of visible light is obtained and the electroconductivesheet is also easily handled.

Thicknesses of the metal silver portions provided on the firsttransparent substrate 14A and the second transparent substrate 14B canbe appropriately determined according to the thicknesses of coatings forthe silver salt containing layer, which are applied onto the firsttransparent substrate 14A and the second transparent substrate 14B. Thethickness of the metal silver portion can be selected from 0.001 mm ormore and 0.2 mm or less, but preferably is 30 μm or less, morepreferably is 20 μm or less, further preferably is 0.01 μm or more and 9μm or less, and most preferably is 0.05 μm or more and 5 μm or less. Inaddition, the metal silver portion preferably forms a pattern shape. Themetal silver portion may be formed of one layer, and may also be amultilayer structure of two or more layers. When the metal silverportion forms the pattern shape and is the multilayer structure of twoor more layers, different color sensitivities can be given to thestructure so as to be capable of being sensitized to differentwavelengths. Thereby, when each layer is exposed to light having achanged light exposure wavelength, different patterns can be formed onthe layers.

As the thickness of the electroconductive metal portion is thinner, aviewing angle of a display panel becomes wider, which is preferable forapplication of a touch panel, and it is required to thin the film alsofrom the point of enhancing the visibility. From such a viewpoint, thethickness of the layer formed of the electroconductive metal which iscarried on the electroconductive metal portion is preferably less than 9μm, more preferably is 0.1 μm or more and less than 5 μm, and furtherpreferably is 0.1 μm or more and less than 3 μm.

In the present embodiment, the thickness of the above described appliedsilver salt containing layer is controlled, thereby a metal silverportion having a desired thickness is formed. Furthermore, because thethickness of the layer formed of the electroconductive metal particlescan be freely controlled by the physical development and/or the platingtreatment, the first electroconductive sheet 12A and the secondelectroconductive sheet 12B even having a thickness of less than 5 μmand preferably of less than 3 μm can be easily formed.

It is needless to say that an electroconductive sheet and a touch panelaccording to the present invention are not limited to the abovedescribed embodiments and can adopt various structures without departingfrom the gist of the present invention. In addition, theelectroconductive sheet and the touch panel can be used while beingappropriately combined with technologies disclosed in Japanese PatentApplication Laid-Open No. 2011-113149, Japanese Patent ApplicationLaid-Open No. 2011-129501, Japanese Patent Application Laid-Open No.2011-129112, Japanese Patent Application Laid-Open No. 2011-134311,Japanese Patent Application Laid-Open No. 2011-175628 and the like.

EXAMPLES

The present invention is more specifically described below withreference to examples of the present invention. Incidentally, materials,amounts to be used, ratios, contents of treatment, treatment proceduresand the like, which are described in the following examples, can beappropriately changed unless they deviate from the scope of the presentinvention. Accordingly, the scope of the present invention should not berestrictively interpreted by the specific examples which are describedbelow.

A transmittance or an aperture ratio was measured and visibility wasevaluated for a multilayered electroconductive sheet relating to eachsample.

(Silver Halide Photosensitive Material)

An emulsion was prepared which contained 10.0 g of gelatin with respectto 150 g of Ag in an aqueous medium and contained silveriodobromochloride particles (I=0.2 mol % and Br=40 mol %) with a sphereequivalent mean diameter of 0.1 μm.

In addition, K3Rh2Br9 and K2IrCl6 were added into this emulsion so thatthe concentration became 10⁻⁷ (mole/mole silver), thereby doping thesilver bromide particles with a Rh ion and an Ir ion. Into thisemulsion, Na2PdCl4 was added, and the resultant emulsion was furthersubjected to gold sulfur sensitization with the use of chloroauric acidand sodium thiosulfate, and then was applied onto the first transparentsubstrate 14A and the second transparent substrate 14B (here, both arepolyethylene terephthalate (PET)) together with a gelatin hardener sothat the amount of silver in coating was 10 g/m². At this time, thevolume ratio of Ag/gelatin was controlled to be 2/1.

The emulsion was applied onto a PET substrate having a width of 30 cmwith a width of 25 cm and at 20 m per minute, and both ends of the PETsupport were cut off by 3 cm so as to leave 24 cm of a central part ofthe coated portion, and a silver halide photosensitive material with arolled form was obtained.

(Light Exposure)

Patterns of light exposure for the first electroconductive sheet 12Awere patterns illustrated in FIG. 1 and FIG. 3, and patterns of lightexposure for the second electroconductive sheet 12B were patternsillustrated in FIG. 4A, FIG. 4B and FIG. 6B. The first transparentsubstrate 14A and the second transparent substrate 14B with an A4 size(210 mm×297 mm) were exposed to light. The light exposure was conductedby using a parallel light which was emitted from a high pressure mercurylamp of a light source, through photomasks of the above describedpatterns. Incidentally, samples of the electrode terminal 60A and theelectrode terminal 60B of the first electroconductive sheet 12A and thesecond electroconductive sheet 12B were each prepared with every patternillustrated in FIGS. 1 to 3.

(Development Treatment)

Formulation of 1 L of Developing Solution

Hydroquinone 20 g  Sodium sulfite 50 g  Potassium carbonate 40 g Ethylenediaminetetraacetic acid 2 g Potassium bromide 3 g Polyethyleneglycol 2000 1 g Potassium hydroxide 4 g pH adjusted to 10.3

Formulation of 1 L of Fixing Solution

Ammonium thiosulfate liquid (75%) 300 ml Ammonium sulfite monohydrate 25g 1,3-diaminopropane tetraacetic acid 8 g Acetic acid 5 g Ammonia water(27%) 1 g pH adjusted to 6.2

The photosensitive material which was exposed to light was subjected toan automatic developing machine FG-710PTS made by FUJIFILM Corporationby using the above described treatment agents, and was treated ontreatment conditions of: development at 35° C. for 30 seconds, fixing at34° C. for 23 seconds, and washing by running water (5 L/min) for 20seconds.

Experiment 1 (Sample 1-1) Example

The electroconductive parts (first electrode pattern 16A and secondelectrode pattern 16B) of the produced first electroconductive sheet 12Aand the second electroconductive sheet 12B have transmittances of 83%.The electrode terminal 60A and the electrode terminal 60B of theproduced first electroconductive sheet 12A and the secondelectroconductive sheet 12B have patterns shown in FIG. 1 andtransmittances of 63%.

(Sample 1-2) Example

Sample 1-2 was prepared similarly to Sample 1-1 except that thetransmittances of the electrode terminal 60A and the electrode terminal60B of the produced first electroconductive sheet 12A and the secondelectroconductive sheet 12B were controlled to be 80%.

(Sample 1-3) Comparative Example

Sample 1-3 was prepared similarly to Sample 1-1 except that thetransmittances of the electrode terminal 60A and the electrode terminal60B of the produced first electroconductive sheet 12A and the secondelectroconductive sheet 12B were controlled to be 60%.

(Sample 1-4) Comparative Example

Sample 1-4 was prepared similarly to Sample 1-1 except that thetransmittances of the electrode terminal 60A and the electrode terminal60B of the produced first electroconductive sheet 12A and the secondelectroconductive sheet 12B were controlled to be 83%.

(Sample 1-5) Example

The electroconductive parts (first electrode pattern 16A and secondelectrode pattern 16B) of the produced first electroconductive sheet 12Aand the second electroconductive sheet 12B have transmittances of 90%.The electrode terminal 60A and the electrode terminal 60B of theproduced first electroconductive sheet 12A and the secondelectroconductive sheet 12B have patterns shown in FIG. 1 andtransmittances of 70%.

(Sample 1-6) Example

Sample 1-6 was prepared similarly to Sample 1-5 except that thetransmittances of the electrode terminal 60A and the electrode terminal60B of the produced first electroconductive sheet 12A and the secondelectroconductive sheet 12B were controlled to be 87%.

(Sample 1-7) Comparative Example

Sample 1-7 was prepared similarly to Sample 1-5 except that thetransmittances of the electrode terminal 60A and the electrode terminal60B of the produced first electroconductive sheet 12A and the secondelectroconductive sheet 12B were controlled to be 67%.

(Sample 1-8) Comparative Example

Sample 1-8 was prepared similarly to Sample 1-5 except that thetransmittances of the electrode terminal 60A and the electrode terminal60B of the produced first electroconductive sheet 12A and the secondelectroconductive sheet 12B were controlled to be 90%.

(Sample 1-9) Example

The electroconductive parts (first electrode pattern 16A and secondelectrode pattern 16B) of the produced first electroconductive sheet 12Aand the second electroconductive sheet 12B have transmittances of 83%.The electrode terminal 60A and the electrode terminal 60B of theproduced first electroconductive sheet 12A and the secondelectroconductive sheet 12B have patterns shown in FIG. 2 andtransmittances of 63%.

(Sample 1-10) Example

Sample 1-10 was prepared similarly to Sample 1-9 except that thetransmittances of the electrode terminal 60A and the electrode terminal60B of the produced first electroconductive sheet 12A and the secondelectroconductive sheet 12B were controlled to be 80%.

(Sample 1-11) Comparative Example

Sample 1-11 was prepared similarly to Sample 1-9 except that thetransmittances of the electrode terminal 60A and the electrode terminal60B of the produced first electroconductive sheet 12A and the secondelectroconductive sheet 12B were controlled to be 60%.

(Sample 1-12) Comparative Example

Sample 1-12 was prepared similarly to Sample 1-9 except that thetransmittances of the electrode terminal 60A and the electrode terminal60B of the produced first electroconductive sheet 12A and the secondelectroconductive sheet 12B were controlled to be 83%.

(Sample 1-13) Example

The electroconductive parts (first electrode pattern 16A and secondelectrode pattern 16B) of the produced first electroconductive sheet 12Aand the second electroconductive sheet 12B have transmittances of 83%.The electrode terminal 60A and the electrode terminal 60B of theproduced first electroconductive sheet 12A and the secondelectroconductive sheet 12B have patterns shown in FIG. 3 andtransmittances of 63%.

(Sample 1-14) Example

Sample 1-14 was prepared similarly to Sample 1-13 except that thetransmittances of the electrode terminal 60A and the electrode terminal60B of the produced first electroconductive sheet 12A and the secondelectroconductive sheet 12B were controlled to be 80%.

(Sample 1-15) Comparative Example

Sample 1-15 was prepared similarly to Sample 1-13 except that thetransmittances of the electrode terminal 60A and the electrode terminal60B of the produced first electroconductive sheet 12A and the secondelectroconductive sheet 12B were controlled to be 60%.

(Sample 1-16) Comparative Example

Sample 1-16 was prepared similarly to Sample 1-13 except that thetransmittances of the electrode terminal 60A and the electrode terminal60B of the produced first electroconductive sheet 12A and the secondelectroconductive sheet 12B were controlled to be 83%.

<Measurement of Transmittance>

Total luminous transmittance was measured for the firstelectroconductive sheet 12A and the second electroconductive sheet 12Bwith the use of a photometer. A photometer TC-HIIIDPK made by TokyoDenshoku.co., Ltd. was used for the measurement.

<Evaluation of Visibility>

Projected capacitive touch panels were produced with the use of each ofthe multilayered electroconductive sheets relating to the abovedescribed samples. Each touch panel was installed on a turntable, aliquid crystal display device was driven and white was displayed. Atthis time, it was visually checked whether a shadow (portion whichbecomes dark) could be recognized or not, in the vicinity of anelectrode terminal of a sensing region.

The touch panel having superior visibility was evaluated as A, the touchpanel having adequate (good) visibility was evaluated as B, the touchpanel in which the visibility was not practically affected was evaluatedas C, and the touch panel having inferior visibility was evaluated as D.

<Evaluation of Response Speed>

The touch panel having a superior response speed was evaluated as A, thetouch panel having an adequate response speed was evaluated as B, thetouch panel in which a response speed did not practically become aproblem was evaluated as C, and the touch panel which had a slowresponse speed and was inferior in detection sensitivity was evaluatedas D.

TABLE 1 Electrode terminal Transmittance of Transmittance of EvaluationSample Corresponding electroconductive electrode Response No. Shape FIG.part terminal Visibility speed 1-1 Frame FIG. 1 88% 68% C A 1-2 FrameFIG. 1 88% 80% A A 1-3 Frame FIG. 1 88% 60% D A 1-4 Frame FIG. 1 88% 87%A C 1-5 Frame FIG. 1 91% 72% C B 1-6 Frame FIG. 1 91% 84% A B 1-7 FrameFIG. 1 91% 64% D B 1-8 Frame FIG. 1 91% 90% A C 1-9 Mesh FIG. 2 88% 68%C A  1-10 Mesh FIG. 2 88% 84% A A  1-11 Mesh FIG. 2 88% 60% D A  1-12Mesh FIG. 2 88% 87% A C  1-13 Frame + mesh FIG. 3 88% 68% C A  1-14Frame + mesh FIG. 3 88% 84% A A  1-15 Frame + mesh FIG. 3 88% 60% D A 1-16 Frame + mesh FIG. 3 88% 87% A C

<Result 1>

As understood from Table 1, the samples which had transmittances in therange according to the present invention out of the samples 1-1 to 1-16showed adequate visibility. In addition, when the touch panels weretouched and operated by a finger, it was found that the samples whichhad transmittances in the range according to the present invention outof the samples 1-1 to 1-16 had a fast response speed and were excellentin detection sensitivity. Furthermore, when the touch panels weretouched at two or more points and operated, the touch panels showedadequate results similarly. Thus, it was confirmed that the touch panelsalso could cope with multitouch.

Experiment 2 (Sample 2-1) Example

The electroconductive parts (first electrode pattern 16A and secondelectrode pattern 16B) of the produced first electroconductive sheet 12Aand the second electroconductive sheet 12B have aperture ratios of 90%.The electrode terminal 60A and the electrode terminal 60B of theproduced first electroconductive sheet 12A and the secondelectroconductive sheet 12B have patterns shown in FIGS. 5A and 5B, andaperture ratios of 70%.

(Sample 2-2) Example

Sample 2-2 was prepared similarly to Sample 2-1 except that the apertureratios of the electrode terminal 60A and the electrode terminal 60B ofthe produced first electroconductive sheet 12A and the secondelectroconductive sheet 12B were controlled to be 89.9%.

(Sample 2-3) Comparative Example

Sample 2-3 was prepared similarly to Sample 2-1 except that the apertureratios of the electrode terminal 60A and the electrode terminal 60B ofthe produced first electroconductive sheet 12A and the secondelectroconductive sheet 12B were controlled to be 68%.

(Sample 2-4) Comparative Example

Sample 2-4 was prepared similarly to Sample 2-1 except that the apertureratios of the electrode terminal 60A and the electrode terminal 60B ofthe produced first electroconductive sheet 12A and the secondelectroconductive sheet 12B were controlled to be 90%.

(Sample 2-5) Example

The electroconductive parts (first electrode pattern 16A and secondelectrode pattern 16B) of the produced first electroconductive sheet 12Aand the second electroconductive sheet 12B have aperture ratios of 97%.The electrode terminal 60A and the electrode terminal 60B of theproduced first electroconductive sheet 12A and the secondelectroconductive sheet 12B have patterns shown in FIGS. 5A and 5B, andaperture ratios of 77%.

(Sample 2-6) Example

Sample 2-6 was prepared similarly to Sample 2-5 except that the apertureratios of the electrode terminal 60A and the electrode terminal 60B ofthe produced first electroconductive sheet 12A and the secondelectroconductive sheet 12B were controlled to be 96.9%.

(Sample 2-7) Comparative Example

Sample 2-7 was prepared similarly to Sample 2-5 except that the apertureratios of the electrode terminal 60A and the electrode terminal 60B ofthe produced first electroconductive sheet 12A and the secondelectroconductive sheet 12B were controlled to be 75%.

(Sample 2-8) Comparative Example

Sample 2-8 was prepared similarly to Sample 2-5 except that the apertureratios of the electrode terminal 60A and the electrode terminal 60B ofthe produced first electroconductive sheet 12A and the secondelectroconductive sheet 12B were controlled to be 97%.

(Sample 2-9) Example

The electroconductive parts (first electrode pattern 16A and secondelectrode pattern 16B) of the produced first electroconductive sheet 12Aand the second electroconductive sheet 12B have aperture ratios of 90%.The electrode terminal 60A and the electrode terminal 60B of theproduced first electroconductive sheet 12A and the secondelectroconductive sheet 12B have patterns shown in FIGS. 6A and 6B, andthe aperture ratios of 70%.

(Sample 2-10) Example

Sample 2-10 was prepared similarly to Sample 2-9 except that theaperture ratios of the electrode terminal 60A and the electrode terminal60B of the produced first electroconductive sheet 12A and the secondelectroconductive sheet 12B were controlled to be 89.9%.

(Sample 2-11) Comparative Example

Sample 2-11 was prepared similarly to Sample 2-9 except that theaperture ratios of the electrode terminal 60A and the electrode terminal60B of the produced first electroconductive sheet 12A and the secondelectroconductive sheet 12B were controlled to be 68%.

(Sample 2-12) Comparative Example

Sample 2-12 was prepared similarly to Sample 2-9 except that theaperture ratios of the electrode terminal 60A and the electrode terminal60B of the produced first electroconductive sheet 12A and the secondelectroconductive sheet 12B were controlled to be 90%.

(Sample 2-13) Example

The electroconductive parts (first electrode pattern 16A and secondelectrode pattern 16B) of the produced first electroconductive sheet 12Aand the second electroconductive sheet 12B have aperture ratios of 90%.The electrode terminal 60A and the electrode terminal 60B of theproduced first electroconductive sheet 12A and the secondelectroconductive sheet 12B have patterns shown in FIG. 7 and theaperture ratios of 70%.

(Sample 2-14) Example

Sample 2-14 was prepared similarly to Sample 2-13 except that theaperture ratios of the electrode terminal 60A and the electrode terminal60B of the produced first electroconductive sheet 12A and the secondelectroconductive sheet 12B were controlled to be 89.9%.

(Sample 2-15) Comparative Example

Sample 2-15 was prepared similarly to Sample 2-13 except that theaperture ratios of the electrode terminal 60A and the electrode terminal60B of the produced first electroconductive sheet 12A and the secondelectroconductive sheet 12B were controlled to be 68%.

(Sample 2-16) Comparative Example

Sample 2-16 was prepared similarly to Sample 2-13 except that theaperture ratios of the electrode terminal 60A and the electrode terminal60B of the produced first electroconductive sheet 12A and the secondelectroconductive sheet 12B were controlled to be 90%.

<Measurement of Aperture Ratio>

The aperture ratios of the first electroconductive sheet 12A and thesecond electroconductive sheet 12B were measured with a magnification of3,000 (3,000 times power) using a microscope VHX-200 made by KEYENCECORPORATION.

<Evaluation of Visibility>

Projected capacitive touch panels were produced with the use of each ofthe multilayered electroconductive sheets relating to the abovedescribed samples. Each touch panel was installed on a turntable, aliquid crystal display device was driven and white was displayed. Atthis time, it was visually checked whether a shadow (portion whichbecomes dark) could be recognized or not in the vicinity of an electrodeterminal of a sensing region.

The touch panel having superior visibility was evaluated as A, the touchpanel having adequate (good) visibility was evaluated as B, the touchpanel in which the visibility was not practically affected was evaluatedas C, and the touch panel having inferior visibility was evaluated as D.

<Evaluation of Response Speed>

The touch panel having a superior response speed was evaluated as A, thetouch panel having an adequate response speed was evaluated as B, thetouch panel in which a response speed did not practically become aproblem was evaluated as C, and the touch panel which had a slowresponse speed and was inferior in detection sensitivity was evaluatedas D.

TABLE 2 Electrode terminal Aperture ratio of Aperture ratio EvaluationSample Corresponding electroconductive of electrode Response No. ShapeFIG. part terminal Visibility speed 2-1 Frame FIG. 1 96% 82% C A 2-2Frame FIG. 1 96% 87.0%   A A 2-3 Frame FIG. 1 96% 75% D A 2-4 Frame FIG.1 96% 95% A C 2-5 Frame FIG. 1 99% 85% C B 2-6 Frame FIG. 1 99% 87.0%  A B 2-7 Frame FIG. 1 99% 78% D B 2-8 Frame FIG. 1 99% 98% A C 2-9 MeshFIG. 2 96% 82% C A  2-10 Mesh FIG. 2 96% 87.0%   A A  2-11 Mesh FIG. 296% 75% D A  2-12 Mesh FIG. 2 96% 95% A C  2-13 Frame + mesh FIG. 3 96%82% C A  2-14 Frame + mesh FIG. 3 96% 87.0%   A A  2-15 Frame + meshFIG. 3 96% 75% D A  2-16 Frame + mesh FIG. 3 96% 95% A C

<Result 2>

As is understood from Table 2, the samples which had an aperture ratiosin the range according to the present invention out of the samples 2-1to 2-16 showed adequate visibility. In addition, when the touch panelswere touched and operated by a finger, it was found that the sampleswhich had the aperture ratios in the range according to the presentinvention out of the samples 2-1 to 2-16 had a fast response speed andwere excellent in detection sensitivity. Furthermore, when the touchpanels were touched at two or more points and operated, the touch panelsshowed an adequate results similarly. Thus, it was confirmed that thetouch panels also could cope with multitouch.

It is needless to say that the electroconductive sheet and the touchpanel according to the present invention are not limited to the abovedescribed embodiments and can adopt various structures without departingfrom the gist of the present invention.

What is claimed is:
 1. An electroconductive sheet comprising: anelectrode pattern constructed of a metal thin wire; and an electrodeterminal that is electrically connected to an end of the electrodepattern, wherein a transmittance of the electrode pattern is 83% ormore, and when the transmittance of the electrode pattern is representedby a %, a transmittance of the electrode terminal is (a-20)% or more and(a-3)% or less.
 2. An electroconductive sheet comprising: an electrodepattern constructed of a metal thin wire; and an electrode terminal thatis electrically connected to an end of the electrode pattern, wherein anaperture ratio of the electrode pattern is 90% or more, and when theaperture ratio of the electrode pattern is represented by b %, anaperture ratio of the electrode terminal is (b-20)% or more and (b-0.1)%or less.
 3. The electroconductive sheet according to claim 1, whereinthe electrode terminal includes a mesh shape formed of latticesconstructed of a metal thin wire.
 4. The electroconductive sheetaccording to claim 3, wherein the metal thin wire has a line width of 30μm or less.
 5. The electroconductive sheet according to claim 3, whereinthe metal thin wire is made from an opaque material.
 6. Anelectroconductive sheet comprising: an electrode pattern constructed ofa metal thin wire; and an electrode terminal that is electricallyconnected to an end of the electrode pattern, wherein the electrodeterminal includes a frame shape constructed of a metal thin wire.
 7. Theelectroconductive sheet according to claim 6, wherein when a line widthof the thin wire of the electrode pattern is represented by a (μm), aline width b (μm) of the frame shape of the electrode terminal satisfiesb≧2a or b≧a+5 (μm).
 8. The electroconductive sheet according to claim 7,wherein the line width a (μm) of the thin wire of the electrode patternis 30 μm or less.
 9. The electroconductive sheet according to claim 7,further comprising a mesh shape provided in the frame shape of theelectrode terminal constructed of the metal thin wire, the mesh shapewhich is formed of lattices constructed of a metal thin wire.